Telecommunications device

ABSTRACT

A shelf-type telecommunications device has a back wired board assembly mounted on a back of a shelf unit into which a plurality of plug-in units are inserted side by side. The back wired board assembly has a main back wired board to which at least one plug-in unit is connected and a sub back wired board to which at least one external cable is connected, the outer surface of the main back wired board and the inner surface of the sub back wired board opposing each other. The main back wired board and the sub back wired board are fitted together by using a plurality of relay connectors or pin terminals so as to electrically connect the main back wired board and the sub back wired board to each other without the need for coaxial cables, thus reducing the size of the device.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a shelf-type telecommunicationsdevice.

[0003] 2. Description of the Related Art

[0004] At present, a shelf-type SONET MUX is widely used as one type oftelecommunications device on trunk lines in telephone networks in NorthAmerica. As demand for telecommunications services has increased inrecent years telecommunications devices for integrating a variety ofdifferent functions added to the SONET MUX, including data interfaces,ATM switches, etc., have come to be developed.

[0005] At the same time, however, the integration of different functionstends to lead to an increase in the overall size of thetelecommunications device. As the amount of space in which to placetelecommunications devices tends to be limited, smallness of size is animportant factor in such devices.

[0006]FIG. 1 is a schematic structural diagram of a conventionaltelecommunications device 10. The telecommunications device 10 has ashelf structure. To the back of the shelf unit 11 are fixedly mounted amain back wired board 12 and a sub back wired board 13. Additionally, aback cover 14 is attached. Within the shelf unit 11 a plug-in unit 15 isinserted and installed. An external cable 21 is connected to the back ofthe telecommunications device 10.

[0007] The separation of the back wired board into a main back wiredboard 12 and a sub back wired board 13 exists because the electricalconnection between the plug-in unit 15 and the external cable 21 isseparated into the electrical connection of the plug-in unit 15 and theelectrical connection of the external cable 21. That is, the function ofelectrically connecting the plug-in unit is assumed by the main backwired board 12 and the function of electrically connecting the externalcable 21 is assumed by the sub back wired board 13.

[0008] As shown in FIG. 2, the plug-in unit 15 is connected to theplug-in unit connector 16 on the front of the main back wired board 12.The external cable 21 is connected to connector 17 on the sub back wiredboard 13 via an opening 14 a in the back cover 14.

[0009] It should be noted that an electrical connection between the mainback wired board 12 and the sub back wired board 13 is effected by acoaxial cable 18. However, effecting the electrical connection betweenthe main back wired board 12 and the sub back wired board 13 by using acoaxial cable requires space for connecting the ends of each and everycoaxial cable 18.

[0010]FIG. 3 shows rear and side rear views of a conventionaltelecommunications device 10 for integrating a variety of differentfunctions. In keeping with the conventional art, the electricalconnection between the main back wired board 12A and the sub back wiredboard 13A is effected by a coaxial cable 18A. By the integration ofdifferent functions the number of coaxial cables approaches 1,000, withcorresponding space required for connecting the ends of each of thecoaxial cables. As a result, the height H1 of the device 10 increasessubstantially to approximately 16 U, 1 “U” being a standardized unit formeasuring shelf height and equal to approximately 1.75 inches.

[0011] Additionally, as the number of these coaxial cables increases thesize of the space 20 required for bending and accommodating the coaxialcables 18A also increases and, accordingly, the spacing a1 between thesub back wired board 13A and the main back wired board 12A must beenlarged to approximately 30 mm. As a result, the depth of the device10A also increases to a size A1.

SUMMARY OF THE INVENTION

[0012] Accordingly, it is a general object of the present invention toprovide a shelf-type telecommunications device in which the problemsdescribed above are solved.

[0013] The above-described object of the present invention is achievedby providing a telecommunications device, comprising:

[0014] a shelf unit;

[0015] a plurality of plug-in units inserted into the shelf unit anddisposed side by side;

[0016] a main back wired board fixedly mounted to a back of the shelfunit;

[0017] a sub back wired board positioned further to the rear of the mainback wired board;

[0018] a plurality of connectors for plug-in units mounted on an innersurface of the main back wired board so as to be connected to theplug-in units inserted into the shelf unit;

[0019] a plurality of connectors for external cables mounted on an outerside of the sub back wired board so as to be connected to externalcables;

[0020] a plurality of relay connectors mounted on a surface of the mainback wired board, the surface opposing the sub back wired board, andelectrically connected to the plurality of connectors for plug-in units;and

[0021] a plurality of relay connectors mounted on a surface of the subback wired board, the surface opposing the main back wired board, theplurality of relay connectors being electrically connected to theplurality of connectors for external cables,

[0022] wherein the plurality of relay connectors on the main back wiredboard and the corresponding plurality of relay connectors on the subback wired board are fitted together, and the main back wired board andthe sub back wired board are electrically connected to each other.

[0023] By providing a telecommunications device in which relayconnectors between an opposed main back wired board and sub back wiredboard are connected, and thus electrically connecting the main backwired board and the sub back wired board, the need for space withinwhich to connect the terminals of the conventional coaxial cable betweenthe main back wired board and the sub back wired board is eliminated. Byeliminating the need for such additional space there is little need forthe main back wired board and the sub back wired board to increase insize even with an increase in device functions.

[0024] Further, the above-described object of the present invention isachieved by providing a telecommunications device comprising:

[0025] a shelf unit;

[0026] a plurality of plug-in units inserted into the shelf unit anddisposed side by side;

[0027] a main back wired board fixedly mounted on a back of the shelfunit;

[0028] a sub back wired board positioned further to the rear of the mainback wired board;

[0029] a plurality of plug-in unit connectors mounted on an innersurface of the main back wired board so as to be connected to theplug-in units inserted into the shelf unit;

[0030] a plurality of external cable connectors mounted on an outersurface of the sub back wired board so as to be connected to externalcables; and

[0031] a plurality of pin terminals provided on the plurality of plug-inunit connectors, the pin terminals each having two press-fit portions,

[0032] wherein the pin terminals are pressed into and projected throughthe main back wired board toward the sub back wired board, and tipportions of the pin terminals are pressed into the sub back wire board,and the main back wired board and the sub back wired board areelectrically connected to each other.

[0033] By providing a telecommunications device in which the electricalconnection between the main back wired board and the sub back wiredboard is effected by plug-in unit connector pin terminals, it ispossible to reduce the space between the opposed main back wired boardand sub back wired board by approximately one third as opposed to anelectrical connection effected by connecting relay connectors betweenthe main back wired board and the sub back wired board.

[0034] Additionally, the above-described object of the present inventionis also achieved by providing a telecommunications device comprising:

[0035] a shelf unit;

[0036] a plurality of plug-in units inserted into the shelf unit anddisposed side by side;

[0037] a main back wired board fixedly mounted to a back of the shelfunit;

[0038] a sub back wired board positioned further to the rear of the mainback wired board;

[0039] a plurality of connectors for plug-in units mounted on an innersurface of the main back wired board so as to be connected to theplug-in units inserted into the shelf unit;

[0040] a plurality of connectors for external cables mounted on an outerside of the sub back wired board so as to be connected to externalcables;

[0041] a plurality of pin terminals provided on the plurality of plug-inunit connectors, tip portions of the pin terminals being inserted intoand projected through the main back wired board; and

[0042] a plurality of relay connectors mounted on a surface of the subback wired board, the surface opposing the main back wired board, theplurality of relay connectors being electrically connected to theplurality of connectors for external cables,

[0043] wherein tip portions of the plurality of plug-in unit connectorpin terminals are connected to the plurality of relay connectors on thesub back wired board, and the main back wired board and the sub backwired board are electrically connected to each other.

[0044] By providing a telecommunications device in which the electricalconnection between the main back wired board and the sub back wiredboard is effected by the plug-in unit connector pin terminals and thesub back wired board relay connectors, the need for relay connectors onthe main back wired board is eliminated.

[0045] Other objects, features and advantages of the present inventionwill become more apparent from the following detailed description whenread in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0046]FIG. 1 is a schematic structural diagram of a conventionaltelecommunications device;

[0047]FIG. 2 is a planar view of a portion of the telecommunicationsdevice depicted in FIG. 1;

[0048]FIG. 3 shows rear and side rear views of a conventionaltelecommunications device for integrating a variety of differentfunctions;

[0049]FIG. 4 is a diagram of a first embodiment of a telecommunicationsdevice for integrating different functions according to the presentinvention;

[0050]FIG. 5 is a block diagram of the telecommunications devicedepicted in FIG. 4;

[0051]FIG. 6 is a diagram of the telecommunications device depicted inFIG. 4;

[0052]FIG. 7 is a detailed diagram of the side view of thetelecommunications device depicted in FIG. 6;

[0053]FIG. 8 shows a rear side view of the telecommunications devicedepicted in FIG. 4 in a state of installation in a rack;

[0054]FIG. 9 shows an exploded view of the telecommunications device inFIG. 4;

[0055]FIG. 10 is an exploded rear view of the telecommunications devicedepicted in FIG. 4;

[0056]FIG. 11 is a diagram depicting the fixed mounting of a relayconnector of the main back wired board;

[0057]FIG. 12 is a diagram of the electrical connection between the mainback wired board and the sub back wired board;

[0058]FIG. 13 is a diagram showing the connection of the plug-in unit tothe back wired board;

[0059]FIG. 14 is a diagram for explaining the electrical connection fromthe plug-in unit to the external cable;

[0060]FIG. 15 is a diagram for explaining a method for assembling theback wired board assembly;

[0061]FIG. 16 is a diagram for explaining a provisional mounting of therelay connector to the sub back wired board;

[0062]FIG. 17 is a diagram for explaining the interconnection of relayconnectors on the back wired board;

[0063]FIG. 18 is a diagram of a second example of a provisional mountingof a relay connector on the sub back wired board;

[0064]FIG. 19 is a diagram of a third example of a provisional mountingof a relay connector on the sub back wired board;

[0065]FIG. 20 is a diagram of a second example of a back wired boardassembly;

[0066]FIG. 21 is an oblique exploded view of the back wired boardassembly depicted in FIG. 20;

[0067]FIG. 22 is a diagram of a third example of a back wired boardassembly;

[0068]FIG. 23 is a diagram for explaining a method for assembling athird example of the back wired board assembly;

[0069]FIG. 24 is a diagram of the relay connector depicted in FIG. 23;

[0070]FIG. 25 is a diagram of a fourth example of the back wired boardassembly, including an expanded cross-sectional view thereof;

[0071]FIG. 26 is an expanded and exploded view of a portion of the backwired board assembly depicted in FIG. 25;

[0072]FIG. 27 is an oblique view of a spacer;

[0073]FIG. 28 is a diagram for explaining a method of assembling theback wired board assembly depicted in FIG. 25;

[0074]FIG. 29 is a diagram of parts of steps (B) and (C) of FIG. 28;

[0075]FIG. 30 is a diagram showing a method of assembling the back wiredboard assembly depicted in FIG. 25;

[0076]FIG. 31 is a diagram of a fifth example of a back wired boardassembly; and

[0077]FIG. 32 is a diagram of a sixth example of a back wired boardassembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0078] A detailed description will now be given of an embodiment of thepresent invention, with reference, initially, to FIG. 4 through FIG. 10.

[0079]FIG. 4 through FIG. 10 are diagrams of a first embodiment of atelecommunications device 50 integrating different functions accordingto the present invention. The telecommunications device 50 is one inwhich such functions as a data interface, ATM switch, etc., have beenadded to the SONET MUX and, as shown in FIG. 5, comprises a circuitconfiguration comprising transport complex 71, service complex 72,switching complex 73, synchronization complex 74 and management complex75.

[0080] The transport complex 71 has a LINE terminal function The servicecomplex 72 has a TRIB terminal function. The switching complex 73 has atraffic connection function between LINE and TRIB in the STS/VT/ATM cellunit. The management complex 75 has a surveillance and qualitycontrol/performance evaluation function.

[0081] The telecommunications device 50 is one that has structured thiscircuit configuration and, as shown in FIG. 4 and FIG. 9, is of ashelf-type construction. On the back surface of the shelf unit 51 a mainback wired board 52 and a sub back wired board 53 are fixedly mountedand, further, a back cover 54 is attached. Inside the shelf a pluralityof plug-in units 55 are inserted from the front of the shelf unit towardthe rear of the shelf unit, and attached at the rear to client interfaceexternal cable 56. An air filter 57 is provided at the front side of theshelf unit 51 so as to cover the plug-in unit 55. Additionally, a frontcover 58 is provided. A plurality of fan units 59 are mounted on the topsurface of the shelf unit 51.

[0082] For reference purposes, the X axis represents width, the Y axisrepresents depth and the Z axis represents height.

[0083] A plurality of plug-in units 55 are connected to the plug-in unitconnectors 60 on the front of the main back wired board 52 and arearranged side by side horizontally and, as shown in FIG. 4, formcomplexes 71-75.

[0084] The back wired board is divided into a main back wired board 52and a sub back wired board 53. The main back wired board 52 serves thefunction of providing a place to which the plug-in unit 55 iselectrically connected. The sub-back wired board 53 serves the functionof providing a place to which the client interface external cable 56 isconnected.

[0085] As shown in FIG. 10, on the sub back wired board 53 are mounted aDS3 interface connector group 80, a DS1 interface connector group 81 anda LAN interface connector group 82. The DS3 interface connector group 80comprises a group of connectors 80 a including an upper section of 18connectors and a central section of 18 connectors arranged at an evenpitch along the horizontal X axis. The DS1 interface connector group 81comprises a group of connectors 81 a including 6 upper connectors and 6lower connectors arranged horizontally. The LAN interface connectorgroup 82 consists of a group of connectors 82 a including 24 centrallypositioned connectors arranged at an even pitch along the horizontal Xaxis.

[0086] As is explained more fully below, the main back wired board 52and the sub back wired board 53 are connected by relay connectorswithout the use of cables. Accordingly, the main back wired board 52 andthe sub back wired board 53 are connected by relay connectors and thusform the back wired board assembly 90. According to this construction,space on the main back wired board 52 and sub back wired board 53 forconnecting the cables is no longer necessary. Accordingly, although theaddition of functions such as data interfaces, ATM switches, etc., tothe SONET MUX increases the number of electrical connections between themain back wired board 52 and the sub back wired board 53 by 1,000 ormore, nevertheless the size of the main back wired board 52 and the subback wired board 53 does not substantially increase.

[0087] Accordingly, the telecommunications device 50 of the presentembodiment requires a height of no more than 10 U, a full 6 U shorterthan the height of the main back wired board and sub back wired boardwhen connected by cables according to the conventional art. Accordingly,such a reduction in the height of the telecommunications device 50, asshown in FIG. 8, makes it possible to install three such devices in the7-foot rack that is standard in North America.

[0088] The width W2 of the telecommunications device 50 corresponds tothe width of the rack, that is, W2=W1.

[0089] Additionally, because the main back wired board 52 and the subback wired board 53 are connected by relay connectors without the use ofcables, the width a2 of the space 63 between the sub back wired board 53and the main back wired board 52 can be reduced by nearly half, from theconventional 30 mm to 17 mm. Accordingly, the telecommunications device50 can be made more compact and, as a result, a passageway for anoperator between devices positioned so that the backs of the devicesface each other may be widened.

[0090] A description will now be given of a back wired board assembly90, to be preceded, however, by a description of the main back wiredboard 52.

[0091] On the main back wired board there is provided a connector device19 as shown in FIG. 11 and FIG. 14. The relay connector device 91comprises a plug-in unit connector 60 on the side toward the Y2direction and a relay connector 92 on the side toward the Y1 direction,as shown in FIG. 10.

[0092] In order to create the connector device 91, a metric connector 93like that shown in FIG. 11(A) is prepared. The metric connector 93 has ashroud 93 a and a longer-than-usual pin terminal 93 b that pierces theshroud 93 a. The pin terminal 93 b has a press-fit portion 93 bl atapproximately a central position of the pin terminal 93 b.

[0093] As shown in FIG. 11(B), the pin 93 b of the metric connector 93is inserted into and through an aperture 52 a in the main back wiredboard 52 and the press-fit portion 93 bl is pressed into the aperture 52a so as to occupy the interior of the aperture 52 a. As a result, themetric connector 93 is firmly fixedly mounted on the main back wiredboard.

[0094] As shown in FIG. 11(C), a sorting plate 94 is fitted to the pinsof the pin terminal 93 b that project horizontally from the surface ofthe main back wired board 52 so as to sort the pins of the pin terminal93 b into predetermined rows. In this state, as shown in FIG. 11(D), ashroud 95 is fitted to the pin terminal 93 b and pressed against the pinterminal 93 b. Since the pins of the pin terminal 93 b have been sortedby the sorting plate 94, the shroud is securely fitted to the entire pinterminal 93 b. The pins of the pin terminal 93 b project into theinterior of the shroud 95, the sorting plate 94 is advanced against thesurface of the main back wired board 52, the holes 95 a of the shroud 95is pressed against an opposing finger-like projecting portion 94 aprojecting from the sorting plate 94, the projecting finger-like portion94 a clamps the pin terminal 93 b, thus fixedly mounting the shroud 95.

[0095] A portion of the metric relay connector 93 that projectshorizontally in the Y2 direction from the main back wired board 52 formsthe plug-in unit connector 60.

[0096] The shroud 95 and the pin terminal 93 b projecting into theinterior of the shroud 95 forms the relay connector 92.

[0097] For the sake of convenience, in FIG. 11 the shroud 93 a of theplug-in unit connector 60 and the shroud 95 of the relay connector 92are shown oriented in the same direction. However, in actuality, asshown in FIG. 10, the plug-in unit connector 60 has the shroud in avertical Z-axis position while that relay connector 92 has the shroud ina front-to-back X-axis position, that is, perpendicular to thehorizontal Y axis position. The relay connector 92 has the shroudpositioned along the X axis because it is matched with the relayconnector 96 on the surface of the rear Y1 side of the sub back wiredboard 53.

[0098] As shown in FIG. 10, FIG. 12(A) and FIG. 14, an relay connector96 is mounted on the surface of the Y1 side of the sub back wired board53. The relay connector 96 opposes the previously mentioned relayconnector 92 and is so disposed that a longer side thereof is positionedalong the horizontal X axis in tandem with the DS3 interface connectorgroup 80, with 8 connectors disposed each in two parallel upper andlower rows.

[0099] Each relay connector 96 is electrically connected to eachconnector 80 a, 81 a and 82 a via the wire pattern in the sub back wiredboard 53.

[0100] With the back wired board assembly 90, as shown in FIG. 12(C) allrelay connectors 96 are fitted to and connected with corresponding relayconnectors 92, thus the sub back wired board 53 and the main back wiredboard 52 are connected by connectors 96 and 92 and electricallyconnected. It should be noted that the materials and dimensions of thehousing are such that each terminal has a predetermined impedance and,as a result, there is impedance matching between relay connectors 96 andrelay connectors 92 at the fitted connection. It should also be notedthat the fitted connection of relay connectors 96 and relay connectors92 also has the effect of connecting the sub back wired board 53 and themain back wired board 52 mechanically as well as electrically.

[0101] A description will be given later of the connection of theconnectors of the sub back wired board 53 with the main back wired board52.

[0102] The plug-in unit 55, as shown in FIG. 13 (A) and (B) involvesfitting the tip of the connector 97 in the direction of the insertioninto the plug-in unit connector 60, connecting and then loading. Theloaded plug-in unit 55 and the client interface external cable 56, asshown in FIG. 13(B) and FIG. 14, are electrically connected by theplug-in unit connector 60 being connected to the relay connector 92,which is connected to the relay connector 96, which is connected to thesub back wired board 53 which is connected to the connector 80 a (81 a,82 a).

[0103] Next, a description will be given of the assembly of the backwired key board assembly 90, that is, of the connection of theconnectors of the sub back wired board 53 to the main back wired board52.

[0104] As shown in FIG. 16, the relay connector 96 is provisionallyaffixed to the sub back wired board 53. The pin terminals 98 of therelay connector 96 have a press-fit portion 98 a that is substantially aFIG. 8 in cross section. A through hole 53 a for soldering is formed onthe sub back wired board 53. A press-fit through hole 100 forpress-fitting the press-fit portion 98 a has a diameter d2 of 0.6 mm.The solder through hole 53 a has a diameter d1 of 0.85 mm, which islarger than the diameter of the press-fit through hole diameter d2 so asto accommodate the press-fit portion 98 a without causing elasticdeformation of the press-fit portion 98 a.

[0105] The pin connector 98 of the relay connector 96 is inserted intothe solder through hole 53 a in the sub back wired board 53. Thepress-fit portion 98 a is thus in a state of lightly contacting theinner surface of the solder through hole 53 a, in such a way that therelay connector 96 does not come loose and fall out even when the subback wired board 53 is positioned horizontally with the relay connector96 facing downward. Moreover, adequate space 101 is left between thepress-fit portion 98 a and the solder through hole 53 a so that the pinterminal 98 can be twisted laterally substantially within the solderthrough hole 53 a at respective angles α (approximately 10 degrees) withrespect to a hypothetical vertical line along the vertical Z axis.

[0106] Accordingly, the relay connector 96 is provisionally mounted onthe sub back wired board 53 in a state in which it can be freely twistedwithin a range of angle β, that is, several degrees, with respect to ahypothetical vertical line along the vertical Z axis.

[0107] As shown in FIG. 15(A), assembly of the back wired board assembly90 involves fitting guide holes on the main back wired board 52 to guidepins 111 and setting the main back wired board 52 onto a press jig 110.

[0108] Next, as shown in FIG. 12(A) and (B) and FIG. 17, a sorting plate112 is fitted lightly onto all the relay connectors 92. A plurality ofholes 113 in the sorting plate 112 having tapered openings straightensthe pins 93 b of the relay connector 92 into perfect rows. By fittingthe sorter plate 112 lightly onto the relay connector any bent pins arestraightened and all the pins 93 b are sorted into positions within+0.05 mm of predetermined perfect rows.

[0109] Next, as shown in FIG. 15(B), an assembler holds the sub backwired board 53 provisionally mounting the relay connector 96 so that therelay connectors 96 face downward, fits the guide holes to the guidepins 111 and gently lowers the sub back wired board 53 onto the mainback wired board 52 as shown in FIG. 15(C). All the relay connectors 96are thus in a state of being fitted to the openings of the correspondingrelay connectors 92.

[0110] Next, as shown in FIG. 15(D), the press jig 114 is set atop thesub back wired board 53, a press (not shown in the drawing) is set atopthe press jig 114, a pressure P is applied to the press and all 24 ofthe relay connectors 96 are at once fitted to their corresponding relayconnectors 92. The relay connectors 96 press upon the sorter plate 112and are fitted to the relay connectors 92.

[0111] It should be noted that the depth of the fitting of the relayconnectors 96 to the relay connectors 92 is reduced by an amount equalto the thickness of the sorter plate 112. However, the thickness of thesorter plate 112 is merely 1 mm, so the contacts 98 b are fullyconnected to the pins 93 b despite the presence of the sort plate 112.

[0112] With the relay connector 96 in a substantially loose state, eachrelay connector 96 is loosened appropriately so as to accommodate anopposite relay connector 92 and is fitted to a shroud 95. That is, anymisalignment between corresponding relay connectors 96 and relayconnectors 92 is absorbed and, accordingly, all 24 relay connectors 96are together fitted normally to corresponding relay connectors 92. Whenthe relay connector 96 is matched to the shroud, even relay connectors96 that are badly misaligned with respect to their corresponding relayconnectors 92 do not exert an excessive force on the shroud 95 and hencethe shroud 95 does not crack.

[0113] Additionally, as described above the sorting plate 112 aligns allthe pins 93 b into predetermined perfect rows within a range of error of+0.05 mm, and thus there is no danger of even one pin being bent and sofailing to be connected. As a result, all of the approximately 1,800pins 93 b are inserted, with a relatively high degree of reliability,into the holes in the relay connector 96, and, accordingly, are normallyand with a high degree of reliability connected to the contact 98 b ofthe tips of the pin terminal 98.

[0114] By using the press jig 114 the sub back wired board 53 ismaintained in substantially a true horizontal position and pressure isexerted on all 24 relay connectors 96 substantially evenly. Byconnecting the intermediate contacts 96 using the press jig 114 asdescribed above, the reliability of the operation of connecting all 24relay connectors 96 to relay connectors 92 is improved.

[0115] Next, screws are tightened atop spacing bolts 115 providedthroughout the main back wired board 52, thus fixedly mounting the subback wired board 53 to the main back wired board 52.

[0116] Next, the pin terminal 98 of the relay connector 96 is solderedto the solder through hole 53 a of the sub back wired board 53. Thesoldering is shown as 116 in FIG. 15(E).

[0117] In the manner described above assembly of the back wired boardassembly 90 is completed.

[0118] A description will now be given of a second and third example ofthe relay connector 96 mounted in a loose state of attachment to the subback wired board 53.

[0119]FIG. 18 shows a second example, in which the pin terminal 98 ofthe relay connector 96 is inserted into and through the solder throughhole 53 a 1 in the sub back wired board 53 and the tip of the pinterminal 98 covered with an adhesive tape 120 and the tape attached to atop surface of the sub back wired board 53 so as to provisionally mountthe pin terminal 98 to the sub back wired board 53 via the solderthrough hole 53 a 1. The provisional mounting of the pin terminal 98 isachieved by the use of adhesive tape 120, so the solder through hole 53a 1 is slightly larger than the solder through hole 53 a used forprovisional mounting using friction as shown in FIG. 16, having adiameter of 1 mm. Accordingly, the pin terminal 98 can be twisted to theleft and right around the vertical Z axis at an angle α1 of up toapproximately 20 degrees, that is, greater than that described above.Accordingly, the relay connector 96 can be freely twisted around thevertical Z axis at an angle β1 greater than that for the previouscomposition, that is, approximately 10 degrees, and therebyprovisionally mounted on the sub back wired board 53.

[0120]FIG. 19 shows a third example. In place of the adhesive tape 120 asheet 121 having a plurality of holes 121 a having an arrangementidentical to the arrangement of the pin terminals 98 is used. Sheet 121is fitted to the sub back wired board 53 in such a way that theplurality of holes 121 a in the sheet 121 are fitted to the tips of thepin terminals 98 inserted into and through the solder through holes 53 a1 of the sub back wired board 53 and attached in such a way as to avoideasy loosening and detachment from the sub back wired board 53.

[0121] Next, a description will be given of a variation of the backwired board assembly, with particular reference to FIG. 20 and FIG. 21.

[0122]FIG. 20 shows a second variation of a back wired board assembly90A, which, as is shown in FIG. 21, provides on the main back wiredboard 52 an relay connector 92A having 24 individual connectors arrangedas a single unit in one flat plane. Similarly, a similarly large relayconnector 96A having 24 individual connectors arranged as a single unitin one flat plane is provided on the sub back wired board 53. Relayconnector 92A and relay connector 96A are connected to each other.

[0123] Relay connector 92A comprises a large sorting plate 94A thatitself combines 24 individual sorter plates 94 and a shroud 95Acorresponding in size to the sorting plate 94A.

[0124] The relay connector 96A of the sub back wired board 53 is fittedto the relay connector 92A using a press to fit a large sorting plate112A that itself combines 24 individual sorting plates 112 onto the tipsof the pins 93 b so as to straighten the pins 93 b.

[0125] It should be noted that there is one relay connector 92A and onerelay connector 96A. As a result, all the pins 93 b of relay connector92A correspond to all the holes in relay connector 96A, and thus relayconnector 96A and relay connector 92A fit together smoothly.

[0126] A description will now be given of a third example, withparticular reference to FIG. 22, FIG. 23 and FIG. 24.

[0127]FIG. 22 shows a third example of a back wired board assembly 90B.The back wired board assembly 90B comprises the main back wired board52, the sub back wired board 53, relay connector 92 connected to relayconnector 96B, and the whole fixedly mounted by screws tightened inspacing bolts 115. There is no sorter plate 112 like that shown in FIG.12, so the interval a3 of space 63 between the sub back wired board 53and the main back wired board 52 is approximately 16 mm, that is,approximately 1 mm less than that shown in the back wired board assembly90 shown in FIG. 6 and FIG. 7. The lack of a sorter plate 112 arisesfrom the method of assembly, which precludes the need for such sorterplate 112.

[0128] The back wired board assembly 90B, as shown in FIG. 23(A)comprises a main back wired board 52 that is connector device 90, theguide holes of which are fitted to the guide pins 111 and set on thepress jig 110. Next, as shown in FIG. 23(B), the relay connectors 96Bdepicted in FIG. 24 are one by one fitted to relay connectors 92. Nosorter plate is used, and the pin terminals 98B are positioned so as toface up.

[0129] Next, as shown in FIG. 23(C), the assembler holds the sub backwired board 53 in both hands, fits the guide holes to the guide pins111, gently lowers the sub back wired board 53 so as to fit the solderthrough holes 53 a 2 to the corresponding pin terminals 98B. The solderthrough holes 53 a 2 have a large diameter and the pin terminals 98Bhave pointed tips 98Ba so as to ease the fitting of the individualsoldering through holes 53 a 2 to their corresponding pin terminals 98B.

[0130] Next, the screws are tightened to the spacing bolts 115 on thesub back wired board 53 and the pin terminals 98B of the relayconnectors 96B are soldered to the soldering through holes 53 a 1 of thesub block wired board 53.

[0131] As can be readily appreciated from the above description, theback wired board assembly 90B can be assembled without the use of apress. Additionally, it should be noted that an relay connector 96 likethat depicted in FIG. 12 may be used in place of the relay connector96B.

[0132] A description will now be given of a fourth example of a backwired board assembly 90, with particular reference to FIG. 25 throughFIG. 30.

[0133]FIG. 25 shows a fourth example of a back wired board assembly 90C.The back wired board assembly 90C is assembled such that the main backwired board 52 and sub back wired board 53 are fixedly mounted in such away that by use of spacing bolts 115 and screws the main back wiredboard 52 and sub back wired board 53 are spaced apart, being connectedby the pin terminals 93 c of the connector 93C, that is, the connector60. An auxiliary spacer 130 like that shown in FIG. 27 is fixedlymounted on an upper surface of the sub back wired board 53. Unlike theback wired board assemblies 90, 90A and 90B depicted in FIG. 10, FIG. 20and FIG. 22, this example has no relay connector 92 on the main backwired board side 52 and no relay connector 96 on the sub back wiredboard 53. As a result, the interval a4 of the space 63 between the mainback wired board 52 and the sub back wired board 53 is 3-7 mm, that is,approximately 10 mm less than that in the back wired board assemblies90, 90A and 90B shown in FIG. 10, FIG. 20 and FIG. 22. Accordingly, bythe use of this back wired board assembly 90C, the A2 depth dimensionshown in FIG. 4 can be decreased by 12 inches or more, thereby making itpossible to achieve a shorter telecommunications device.

[0134] As shown in FIG. 26, connector 93C has a pin terminal 93Cbthrough which penetrates through a shroud 93Ca. The pin terminal 93Cb isan action pin terminal having two press-fit portions and, from the top,is structured as follows: The pin terminal portion 93Cb1, the insertionportion 93Cb2 for inserting into the shroud 93Ca, the first press-fitportion 93Cb3, the pin portion 93Cb4, the second press-fit portion 93Cb5and the tip portion 93Cb6. The size of the second press-fit portion93Cb5 is slightly smaller than the size of the first press-fit portion93Cb3. The insertion portion 93Cb2 of the pin terminal 93Cb is pressedinto and fixedly mounted at the through hole of the shroud 93Ca, suchthat the first press-fit portion 93Cb3, the pin portion 93Cb4, thesecond press-fit portion 93Cb5 and the tip portion 93Cb6 project fromthe bottom of the shroud 93Ca.

[0135] The main back wired board 52 has a press-fit through hole 52 bhaving a diameter corresponding to the size of the first press-fitportion 93Cb3 of the pin terminal 93Cb. The sub back wired board 53 hasa press-fit through hole 53 b having a diameter corresponding to thesize of the second press-fit portion 93Cb5. The diameter of thepress-fit through hole 53 b of the sub back wired board 53 is slightlysmaller than the diameter of the present invention fit through hole 52 bof the main back wired board.

[0136] The first press-fit portion 93Cb3 is inserted into the press-fitthrough hole 52 b of the main back wired board 52. The second press-fitportion 93Cb5 is inserted into the press-fit through hole 53 b of thesub back wired board 53. As a result, the pin portion 93Cb4 cuts acrossspace 63. The tip portion 93Cb6 projects from the surface of the subback wired board 53.

[0137] A description will now be given of the assembly of the back wiredboard assembly 90C described above, with initial reference to FIG. 28.

[0138] As shown in FIG. 28(A), the main back wired board 52 and the subback wired board to which the supplementary spacer 130 is fixedlymounted, together with an auxiliary board 131 positioned beneath andcontacting the bottom surface of the sub back wired board 53, arefixedly mounted at intervals using screws tightened to spacing bolts115. This entire assemblage is then placed atop a press jig 132 and theconnector 93C is set to the main back wired board 52 as shown in FIG.28(B) and FIG. 29(A). The connector 93C is connected such that thesecond press-fit portion 93Cb5 is inserted into and through thepress-fit through hole 52 b provided on the main back wired board 52,and the second press-fit portion 93Cb3 is inserted into the mouth of thepress-fit through hole 52 b. In this state, the tip portion 93Cb6opposes a tapered guide hole 130 a provided in the auxiliary spacer 130.In some cases, the tip portion 93Cb6 is guided by the tapered portion ofthe tapered guide hole 130 a and inserted into the press-fit throughhole 53 b of the sub back wired board 53. It should be noted that theauxiliary spacer 130 is provided in order to guide the tip portion 93Cb6into the press-fit through hole 53 b of the sub back wired board 53using the tapered guide hole 130 a.

[0139] A through hole 131 a having a diameter larger than the press-fitthrough hole 53 b to which it corresponds is formed in the auxiliaryboard 131, and is provided in order to receive the tip portion 93Cb6that is projected from the bottom surface of the sub back wired board53.

[0140] The press 132 has rams 134 provided at positions corresponding toeach of the individual connectors 93C. Each such ram 134 operatesindependently of the others. The press 132 is operated and theindividual press rams 134 press down upon each of the connectors setatop the main back wired board 52 as shown in FIG. 28(C), achieving astate like that depicted in FIG. 29(B). The first press-fit portion93Cb3 is pressed into the press-fit through hole 52 b of the main backwired board 52. The second press-fit portion 93Cb5 is inserted into thepress-fit through hole 53 b of the sub back wired board 53. The shroud93Ca contacts the upper surface of the main back wired board 52. The tipportion 93Cb6 is guided by the tapered guide h9ole 130 a into andthrough the press-fit through hole 53 b of the sub back wired board 53,and projects below the bottom surface of the sub back wired board 53 towithin a thickness of the auxiliary board 131.

[0141] Each of the connectors 93C is pressed down individually, so evena small amount of pressure P1 exerted on the rams 134 is sufficient.Additionally, after all the connectors 93C have been pressed into placeas shown in FIG. 28(D), the auxiliary board 131 is removed and thescrews tightened once more, thereby producing the back wired boardassembly 90C depicted in FIG. 28(E).

[0142] As can be readily appreciated from the above description, theback wired board assembly can be assembled efficiently and stablely.

[0143]FIG. 30 shows another method for assembling the back wired boardassembly 90C, in which a device is used to press and insert one at atime each of the pin terminals 93Cb having two press-fit portions.

[0144] The initial preparatory stage is identical to that shown in FIG.28(A). As shown in FIG. 30 (A), the main back wired board 52 and the subback wired board 53 to which is fixedly mounted an auxiliary spacer 130,together with an auxiliary board 131 positioned beneath and contactingthe sub back wired board 53, are spaced and fixedly mounted by screwstightened to spacing bolts 115. Next, this assemblage is set to the pinpressing device, a shroud 93Ca placed on the upper surface and theterminal pins 93Cb, one at a time, from the top of the shroud 93Ca, arepassed through the shroud 93Ca and the main back wired board 52 andpressed into the sub back wired board 53 as shown in FIG. 30(B) and (C),thus completing assembly of the back wired board assembly 90C as shownin FIG. 30(C).

[0145] It should be noted that the pin terminal 93Cb is inserted asindependent parts and so even slight pressure is sufficient to ensureinsertion of the pin terminal 93Cb, thus eliminating the need to bracethe sub back wired board 53 with a brace plate or other, similar means.

[0146] A fifth example of a back wired board assembly will now bedescribed, with reference to FIG. 31.

[0147]FIG. 31 shows a fifth example of the back wired board assembly90D. The main back wired board 52 and the sub back wired board 53 arefixedly mounted at an interval via screws tightened through spacingbolts 115. The top surface of the main back wired board 52 fixedlymounts a connector 93D (connector 60). The tip portions of the pinterminals 93 Db of the connector 93D are connected to relay connector 96on the top surface of the sub back wired board 53. The main back wiredboard 52 and the sub back wired board 53 are electrically connected bythe pin terminal 93 Db of the connector 93D and the relay connector 96.

[0148]FIG. 32 shows a sixth example of the back wired board assembly90D. The main back wired board 52 and the sub back wired board 53 arefixedly mounted at an interval via screws tightened through spacingbolts 115. A connector 93E is fixedly mounted on the top surface of themain back wired board 52. The pin terminal 93Eb of the connector 93E isstraightened by a sorting plate 140 on the bottom surface of the mainback wired board 52. The tip portion of the pin terminal 93Eb isinserted into and through the through hole 53 c provided in the sub backwired board 53 and connected by an electrically conductive adhesiveagent 142. It should be noted that solder may be used in place of theelectrically conductive adhesive agent 142.

[0149] The above description is provided in order to enable any personskilled in the art to make and use the invention and sets forth the bestmode contemplated by the inventors of carrying out their invention.

[0150] The present invention is not limited to the specificallydisclosed embodiments and variations, and modifications may be madewithout departing from the scope of the present invention.

[0151] The present application is based on Japanese priority applicationNo. 10-304394 filed on Oct. 26, 1998, the entire contents of which arehereby incorporated by reference.

What is claimed is:
 1. A telecommunications device, comprising: a shelfunit; a plurality of plug-in units inserted into the shelf unit anddisposed side by side; a main back wired board fixedly mounted to a backof the shelf unit; a sub back wired board positioned further to the rearof the main back wired board; a plurality of connectors for plug-inunits mounted on an inner surface of the main back wired board so as tobe connected to the plug-in units inserted into the shelf unit; aplurality of connectors for external cables mounted on an outer side ofthe sub back wired board so as to be connected to external cables; aplurality of relay connectors mounted on a surface of the main backwired board, the surface opposing the sub back wired board, andelectrically connected to the plurality of connectors for plug-in units;and a plurality of relay connectors mounted on a surface of the sub backwired board, the surface opposing the main back wired board, theplurality of relay connectors being electrically connected to theplurality of connectors for external cables, wherein the plurality ofrelay connectors on the main back wired board and the correspondingplurality of relay connectors on the sub back wired board are fittedtogether, and the main back wired board and the sub back wired board areelectrically connected to each other.
 2. The telecommunications deviceas claimed in claim 1, wherein the main back wired board and the subback wired board form a single back wired board assembly, the pluralityof relay connectors on the main back wired board and the plurality ofrelay connectors on the sub back wired board being fitted together andelectrically connected.
 3. The telecommunications device as claimed inclaim 2, wherein the back wired board assembly is assembled so that aplurality of relay connectors on the sub back wired board are initiallyprovisionally mounted in a loose state on the sub back wired board, andthe relay connectors loosely mounted on the sub back wired board aresimultaneously fitted to the corresponding plurality of relay connectorson the main back wired board.
 4. The telecommunications device asclaimed in claim 2, wherein the back wired board assembly is assembledso that plurality of relay connectors on the sub back wired board areinitially provisionally mounted in a loose state on the sub back wiredboard, a plurality of pin terminals of a plurality of relay connectorsare arranged on the main back wired board, a sorting plate straightensthe pin terminals, and the relay connectors on the sub back wired boardare fitted to corresponding relay connectors on the main back wiredboard so as to depress the sorting plate.
 5. The telecommunicationsdevice as claimed in claim 3, wherein the provisional mounting in aloose state of the plurality of relay connectors on the sub back wiredboard is accomplished by loosely fitting a plurality of terminals of theplurality of relay connectors to a plurality of holes in the sub backwired board.
 6. The telecommunications device as claimed in claim 3,wherein the provisional mounting in a loose state of the plurality ofrelay connectors on the sub back wired board is accomplished by looselyfitting the plurality of terminals of the plurality of relay connectorsto and through a plurality of holes in the sub back wired board andholding the terminals in place by attaching tape to the tips of theterminals.
 7. The telecommunications device as claimed in claim 2,wherein the back wired board assembly is assembled so that a pluralityof sub back wired board relay connectors not mounted on the sub backwired board are fitted to and connected to each of the plurality ofrelay connectors on the main back wired board, the sub back wired boardis guided by a plurality of guide pins and brought into proximity withpin terminals protruding from back surfaces of the plurality of sub backwired board relay connectors, and a plurality of through holes in thesub back wired board and the pin terminals are fitted together.
 8. Atelecommunications device comprising: a shelf unit; a plurality ofplug-in units inserted into the shelf unit and disposed side by side; amain back wired board fixedly mounted on a back of the shelf unit; a subback wired board positioned further to the rear of the main back wiredboard; a plurality of plug-in unit connectors mounted on an innersurface of the main back wired board so as to be connected to theplug-in units inserted into the shelf unit; a plurality of externalcable connectors mounted on an outer surface of the sub back wired boardso as to be connected to external cables; and a plurality of pinterminals provided on the plurality of plug-in unit connectors, the pinterminals each having two press-fit portions, wherein the pin terminalsare pressed into and projected through the main back wired board towardthe sub back wired board, and tip portions of the pin terminals arepressed into the sub back wire board, and the main back wired board andthe sub back wired board are electrically connected to each other. 9.The telecommunications device as claimed in claim 8, wherein the mainback wired board and the sub back wired board form a single back wiredboard assembly, the main back wired board and the sub back wired boardbeing electrically connected by the pressed pin terminals.
 10. Thetelecommunications device as claimed in claim 9, wherein the back wiredboard assembly is assembled so that the main back wired board and thesub back wired board are fixedly mounted so as to provide a space therebetween, and the plurality of plug-in unit connectors are mountedindividually by pressing and inserting a plurality of pin terminalsthereof through the main back wired board and then through the sub backwired board.
 11. The telecommunications device as claimed in claim 9,wherein the back wired board assembly is assembled so that the main backwired board and the sub back wired board are fixedly mounted so as toprovide a space there between, the plurality of plug-in connector pinterminals being independent parts each individually pressed into andthrough a plug-in unit connector shroud mounted atop the main back wiredboard so as to project into and through the main back wired board andthen into and through the sub back wired board.
 12. A telecommunicationsdevice comprising: a shelf unit; a plurality of plug-in units insertedinto the shelf unit and disposed side by side; a main back wired boardfixedly mounted to a back of the shelf unit; a sub back wired boardpositioned further to the rear of the main back wired board; a pluralityof connectors for plug-in units mounted on an inner surface of the mainback wired board so as to be connected to the plug-in units insertedinto the shelf unit; a plurality of connectors for external cablesmounted on an outer side of the sub back wired board so as to beconnected to external cables; a plurality of pin terminals provided onthe plurality of plug-in unit connectors, tip portions of the pinterminals being inserted into and projected through the main back wiredboard; and a plurality of relay connectors mounted on a surface of thesub back wired board, the surface opposing the main back wired board,the plurality of relay connectors being electrically connected to theplurality of connectors for external cables, wherein tip portions of theplurality of plug-in unit connector pin terminals are connected to theplurality of relay connectors on the sub back wired board, and the mainback wired board and the sub back wired board are electrically connectedto each other.